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T. N. VAIL & J. A. SEELY'.

TELEPHONE CENTRAL STATION APPARATUS.

Patented July 10, 1888.

8440041- l'omy,

UNITED STATES PATENT Orrlcn.

THEODORE N. VAIL, OF BOSTON, 'MASSACHUSETTS, AND JOHN A.'SEEDY,

OF NEW YORK, N. Y.

TELEPHONE CENTRAL- To all whom it may concern:

Beit known that we, THEODORE N. VAIL and JOHN A. SEELY, citizens of the United States, and residents, respectively, of Boston, county of Suffolk, State of Massachusetts, and of the city, county, and State of New York, have jointly invented certain new and useful Improvement-s in Telephone Central-Station Apparatus, of which the following is a specification.

Our invention is an im 'irovcmcnt in the arrangement of telephone apparatus, whereby intercommunication between distant points is facilitated, while the space occupied and the expense of erecting and maintaining such apparatus are reduced,

Our improvement consists in connecting every sub-station line of a group in multiple are with an operators head telephone and in terminating every sub-station line of a groupin a flexible connecting-cord normally resting by force of a gravity or equivalent take-up upon strips, conductors, or connections forming the terminals of said operators telephone. By this means no preliminary signal is necessary, the sub-station merely icmoving his telephone and speaking into the transmitter hisown number or designation and the nu mher or designation of the sub-station required.

The details and arrangement of such a substation, with certain novel and improved features, we have described in another application, to which reference may be had, Serial No. 265,297, filed February 25, 1888.

The drawing illustrates a series of metallic circuits entering a central station, passing through a series of multiple boards, and terminating in a group upon one of these boards.

The circuit C O enters the first board, G,

4.0 passes through a spring-jack, j, forming one of the aggregate number on that board, then through a similar jack on the second. board, G", and terminates. let us suppose, in a group on that board in a flexible cord, m, hav- 5 ing a double-contact plug, 12 q, the two insulated contacts at its base resting upon continuous st rips or contacts 100 and 101'. These. strips or pairs of stripsform the terminals of the opposite ends of linecircuits, and also the terminals, respectively, of a local circuit, 90

STATION APPARATUS.

Patent No. 385,974, dated July 10, 1888.

Serial No. 21L296. (No modeti 91, containing a head telephone, '1, and a transmitter, T, which are continuously in position for use by the operator assigned to that particular group. It is to he observed, therefore, that the operators head telephone and all the sub-station circuits of the group are connected in parallel circuit, and any order or request telephonically transmitted by a sub-station will be heard by the group, who raises the plug 1) q and places it in the jack of the called-for circuit, which jack constitutes-one of the aggregate number on the same board. Each operator has pushbuttons for ringing in either direction and keys for looping a telephone into a circuit after ithas been removed from its normal POSl'. tion.

0 indicates two separate push-buttons, a similar pair being assigned to each circuit of a group. They consist of cylinders of insulating material, each having two bands of conducting material, 7 and 9, 8 and 10. 15, 17, and 19 are three sections of conducting material, as are also 14 16 18. These sections form a continuous conductor, including the bands 9, ll, 10, and 12,when thebuttons are in a normal position. 1 and 2, 3 and 4 are bars of conducting material, each forming the terminals of a generator.

5 and 7, 6 and 8 are contacts for uniting the line and generator when the buttons or either of them is depressed.

S S are springs for returning the buttons 0 c to their normal position. The metal strip 21 furnishes a suitable bearing for the lower end of these buttons.

-There is also a looping-in apparatus for each circuit. This is designed for use when the plug is lifted from its normal contact and it is necessary or desirable to listen to operations on the connected circuits. connections 40 41 from the telephone set '1 to two contacts, 42 43, and the sub-station circuit is electrically connected to two contacts, 44

45, as shown, so that by depressing button (I a telephone setis connectedto the circuit independently of the normal position of the apparatus and without disturbing-the two circuits connected together for conversation.

We will now describe the operation of re- We provide electrical ceiving a call and connecting. two sub-stations. Our operator has the head telephone in posi tion. This telephone is normally connected with one hundred circuits, let us suppose. A call is heard, 200 on 900, the first being the number of the calling station, the second that of the station calledior. The operator immediately raises plug q of the circuit 200, and, if circuit 900 is idle, places said plug in spring'jack 900. This breaks circuit 900 at pointsjj"in its jack, and the points 1) and Q of the two contactplugs connect with points it and 3 respectively. The two metallic circuits now form one continuous metallic circuit containiuga clearing out annunciator at the central station only, being free from the central station telephone, because all behind the jack j of circuit 900 is cut off and the plug of circuit 200 is lifted from its telephone-contact. The central station now dcprtsses the rear pnshbutton to signal the called for sub-station, circuitpassing from circuit 900 to plug 2) q, thence via elements 18, 12, 8, 4, B, 3, 6, and 19. The :alled-for station responds and the conversation is carried on, as is well understood.

Should the central-station operator desire to listen, key cl is depressed, connecting 42 with 55 and 43 with 44, circuit being from the trans mitting-station to plug q. thence cia. cord m to point45, 42, 40, T, T, 41, 43, and 44 to cord at. WVhen conversation is concluded, the calling-station sends an impulse from a generator to line, dropping the annunciator, and the parts are restored to their normal position by the operator \Ve have shown a spring-jack having a dustgnard, p,- but this featn re ofimprovement we have described and claimed in another application, filed March 1, 1888, Serial No. 265,783.

\Vhat we claim, and desire to secure by Letters Patent, is

l. The combination of a central station, a series of sub-stations, a series of metallic cir cuits, one for each substation, connected in parallel at said central station, a telephone-hr strument for each circuit at the substation, a receiving-tclephonc at the central station in a local circuit havingfixed electrical contacts, two separable contacts for each metallic circuit, and a suitable device for separately connecting and lisconnecting the two terminals of each metallic circuit with the terminals of the local circuit.

2. The combination of a series of snb-sta tions, a central station, a series of metalliccircuits, one for each sub-station, a telephoneinstrument for each circuit at the substation. a receiving'telephonc at the central stat-ion, a local circuit having fixed electrical contacts in which the receiving-telephone is pernumently located, a flexible cord forming the terminal of each circuit, and a double-contact switchplug for each cord having electrical contacts registering with the fixed co tacts ofthe local circuit and normally resting thereon, whereby all circuits are connected in parallel with the receivihg-telephone and any circuit may be connected and disconnected therewith il1de pendently.

THEO. N. VA lL. JOHN A. SEELY. Witnesses:

JOHN H. GA'HILL, M. G. Donn. 

